Valve

ABSTRACT

The invention relates to a valve having at least one inlet chamber ( 1 ) and at least one outlet chamber ( 3 ) that can be connected to each other or blocked from each other by means of an actuator ( 5, 12, 13, 14, 15 ), having a control chamber ( 6 ) for controlling the actuator ( 5, 12, 13, 14, 15 ), characterized in that the control chamber ( 6 ) is divided into a first chamber ( 9 ) and a second chamber ( 8 ), wherein the first chamber ( 9 ) and the second chamber ( 8 ) are connected to each other.

The invention relates generally to embodiments of a valve according to the preamble of claim 1.

A valve of the general type under consideration, which may be in the form of, for example, a 2/2-way valve, can be used, for example, for controlling the flow of pressure medium between a pressure medium source and a pressure medium sink. For this purpose, an inlet chamber of the valve is connected via an inlet connection to the pressure medium source and an outlet chamber of the valve is connected via an outlet connection to the pressure medium sink. The valve has a positioning means by which the inlet chamber can be connected to or shut off from the outlet chamber. In the through-flow position the inlet chamber is connected to the outlet chamber and the pressure medium source is therefore connected to the pressure medium sink. In the shut-off position the inlet chamber is disconnected from the outlet chamber and the pressure medium source is therefore disconnected from the pressure medium sink.

The positioning means is usually embodied as a piston. The control of the piston is effected by means of a control chamber, which can be subjected to the pressure medium. The pressure medium can act on the piston via a control face of the piston and thus bring about a movement of the piston. In a configuration of such a valve, which is also referred to as normally closed, the valve is in the shut-off position when the control chamber has been vented. The piston is preloaded by a spring such that the pressure medium cannot flow from the inlet chamber into the outlet chamber. In order to transfer the valve from the shut-off position to the through-flow position, pressurization of the control chamber with the pressure medium is required. During pressurization of the control chamber the pressure medium acts on a control face of the piston, whereby the piston is moved against the force of the spring and therefore opens the path between the inlet chamber and the outlet chamber, so that the pressure medium can flow from the inlet chamber to the outlet chamber.

During pressurization of the control chamber with the pressure medium, the problem can arise that the piston is set into oscillation caused by the activation with the pressure medium, since the piston, in combination with the spring, represents an oscillatory system. This oscillation is undesirable because, firstly, it can cause noise and, secondly, it can even lead to destruction of the valve.

It is therefore an object of the invention to make available a valve in which oscillation of the piston or positioning means caused by activation with the pressure medium is avoided.

This object can be achieved according to the claimed invention by the features specified in claim 1.

In accordance with embodiments of the invention, the control chamber is divided into a first chamber and a second chamber, the first chamber being connected to the second chamber. The division of the control chamber leads to a velocity-dependent damping of the movement of the positioning means during pressurization of the control chamber with the pressure medium. The damping is achieved by two effects. Firstly, the pressure medium is braked as it passes from the first to the second chamber. The pressure medium therefore does not act with its full energy on the control face of the positioning means, as in the case of a unitary control chamber. Secondly, as the positioning means moves an underpressure is produced in the second chamber, since a pressure equalization between the first and second chambers cannot take place correspondingly quickly. The underpressure exerts a force on the positioning means which opposes the movement.

Through the above-described damping, oscillation of the positioning means is prevented. The inventive embodiments therefore enable low-noise and robust valves to be implemented.

Advantageous embodiments of the invention are apparent from the dependent claims and from the exemplary embodiments explained in more detail with reference to the appended drawings, in which:

FIG. 1 shows a cross section of a valve known from the prior art,

FIG. 2 shows a cross section of a valve according to an embodiment of the invention, and

FIG. 3 shows a cross section of a valve according to a further embodiment of the invention.

FIG. 1 shows the cross section of a conventional valve. The valve is used to control the flow of pressure medium between an inlet connection 2 and an outlet connection 4. For this purpose a pressure medium source may, for example, be connected to the input connection 2 and the outlet connection 4 may be connected to a consumer. An inlet chamber 1 can be connected to or disconnected from an outlet chamber 3 by a positioning means 5. In the position shown in FIG. 1, the inlet chamber 1 is disconnected from the outlet chamber 3, so that the pressure medium cannot flow from the inlet connection 2 to the outlet connection 4.

Control of the positioning means 5, which is embodied as a piston 5, is effected via a control chamber 6. In order to control the positioning means 5, the control chamber 6 can be connected via a control chamber connection 7 to a pressure medium source or to a pressure medium sink. The position of the valve shown in FIG. 1 corresponds to a connection of the control chamber 6 to a pressure medium sink. The control chamber 6 is vented. The valve is in its shut-off position, since the positioning means 5 is preloaded by a spring 8 such that the pressure medium cannot flow from the inlet chamber 1 into the outlet chamber 3.

In order to transfer the valve from the shut-off position to the through-flow position, pressurization of the control chamber 6 with the pressure medium is required; that is, the control connection 7 of the control chamber 6 is connected to a pressure source. During pressurization of the control chamber 6 with the pressure medium, the pressure medium acts on a control face of the positioning means 5, whereby the positioning means 5 is moved against the force of the spring 8 and therefore opens the path between the inlet chamber 1 and the outlet chamber 3, so that the pressure medium can flow from the inlet chamber 1 to the outlet chamber 3.

During pressurization of the control chamber 6 with the pressure medium, the problem can arise that the positioning means 5 is set into oscillation caused by the activation with the pressure medium, since the positioning means 5, in combination with the spring 8, represents an oscillatory system. This oscillation is undesirable since, firstly, it can cause noise and, secondly, it can even lead to destruction of the valve.

FIG. 2 shows a cross section of a valve according to an embodiment of the present invention. The fundamental operation of the valve corresponds to the operation described above of the valve shown in FIG. 1, so that a separate description of the fundamental operation is not necessary. According to the depicted embodiment of the invention, the control chamber 6 of the valve is divided into a first chamber 9 and a second chamber 8. The division of the control chamber is effected by means of a screen 10. The first chamber 9 is connected to the second chamber 8 via an aperture 11 of the screen 10. The screen 10 and the aperture 11 of the screen 10 are dimensioned such that they act as a throttle 10, 11. The effect of the throttle 10, 11 is such that, upon pressurization of the first chamber 9 with the pressure medium, the compressed air flowing into the first chamber 9 enters the second chamber 8 in a throttled manner, so that oscillation of the positioning means 5 is avoided.

In order to control the positioning means 5, the first chamber 9 can be connected to a pressure medium source or to a pressure medium sink. In order to move the valve from its shut-off position shown in FIG. 2 to the through-flow position, the first chamber 9 is subjected to the pressure medium. The pressure medium reaches the second chamber 8 from the first chamber 9 via the aperture 11 of the screen 10. The pressure medium, which has thus entered the second chamber 8 acts on the control face of the positioning means 5 and thus causes an actuation of the valve from the shut-off to the through-flow position. The volume of the first chamber 9 is independent of the position of the positioning means 5, whereas the volume of the second chamber 8 depends on the position of the positioning means. In the through-flow position of the valve the volume of the second chamber 8 is larger than in the shut-off position of the valve.

The division of the control chamber 6 brings about a velocity-dependent damping of the movement of the positioning means 5 during pressurization of the control chamber 6 with the pressure medium. The damping is achieved by two effects. Firstly, the pressure medium is braked as it passes from the first chamber 9 to the second chamber 8. The pressure medium therefore does not act with its full energy on the control face of the positioning means 5, as with a unitary control chamber 6. Secondly, during a movement of the positioning means 5, which is greater than is necessary to equalize the forces between the gas force and the spring force (oscillation case), an underpressure is produced in the second chamber 8, since the movement of the positioning means 5 causes an increase in the volume of the second chamber 8 and a pressure equalization between the first chamber 9 and the second chamber 8 cannot take place correspondingly rapidly. The underpressure exerts a force on the positioning means 5 which opposes the movement.

The above-described damping prevents oscillation of the positioning means 5. Therefore, low-noise and robust valves can be implemented.

Advantageously, the two chambers 8, 9 are configured such that the volume of the second chamber 8 is smaller than that of the first chamber 9. Oscillation of the positioning means 5 is prevented especially effectively by these configurations.

To assist the avoidance of oscillation of the positioning means 5, the positioning means 5 can additionally have a stepped configuration in the region of the outlet chamber 3; that is, the positioning means 5 can be stepped on its side opposite its control face.

FIG. 3 shows an embodiment of the inventive valve that can be used in gas or air dryers as a vent or discharge valve. As compared to the valves shown in FIG. 1 and FIG. 2, the positioning means 5 is implemented not by a one-piece piston 5 but by a piston head 12, which is provided with a circumferential seal 13 and is connected to a pressure plate 15 by means of a piston rod 14.

An air dryer for a vehicle compressed air system in which the valve according to FIG. 3 can be used is described in DE 11 2005 002 633 T5. In this document the vent or discharge valve is referred to as a purge valve, which is denoted by reference numeral 22. The purge valve is described, in particular, in paragraphs [0024] and [0030] of DE 11 2005 002 633 T5. According to FIGS. 1 to 3 and paragraph [0024] of this document, the control chamber of the purge valve is formed by a cylindrical section of the body, the cylindrical section being denoted by reference numeral 62 and the body by reference numeral 12 in this document. According to the inventive embodiment of the present application, the cylindrical section of the body, and therefore the control chamber of the purge valve, is divided into two chambers.

Further examples of components/devices in which the valve according to embodiments of the invention can be used include pressure regulators or compressed air supply devices for motor vehicles. Such a compressed air supply device is disclosed, for example, in DE 10 2006 035 772 A1. 

1. A valve, comprising at least one inlet chamber (1) and at least one outlet chamber (3) which can be connected to one another or shut off from one another by means of a positioning means (5, 12, 13, 14, 15), and comprising a control chamber (6) for controlling the positioning means (5, 12, 13, 14, 15), characterized in that the control chamber (6) is divided into a first chamber (9) and a second chamber (8), the first chamber (9) and the second chamber (8) being connected to one another.
 2. The valve as claimed in claim 1, characterized in that the first chamber (9) and the second chamber (8) are connected to one another via a throttle (10, 11).
 3. The valve as claimed in either of the preceding claims, characterized in that the division of the control chamber (6) is effected by a screen (10).
 4. The valve as claimed in claim 3, characterized in that an aperture (11) of the screen (10) acts as the throttle opening (11).
 5. The valve as claimed in any one of the preceding claims, characterized in that the first chamber (9) can be subjected to pressure medium and the volume of the second chamber (8) is dependent on the position of the positioning means (5, 12, 13, 14, 15).
 6. The valve as claimed in any one of the preceding claims, characterized in that the volume of the first chamber (9) is greater than the volume of the second chamber (8).
 7. The valve as claimed in any one of the preceding claims, characterized in that the positioning means (5, 12, 13, 14, 15) is preloaded by a spring (8).
 8. The valve as claimed in any one of the preceding claims, characterized in that the positioning means (5, 12, 13, 14, 15) is a piston (5).
 9. The valve as claimed in any one of the preceding claims, characterized in that the positioning means (5, 12, 13, 14, 15) is stepped in the region of the outlet chamber (3).
 10. The valve as claimed in any one of the preceding claims, characterized in that the valve can be heated.
 11. The valve as claimed in any one of the preceding claims 2 to 10, characterized in that the throttle (10, 11) is dimensioned in such a manner that oscillation of the positioning means (5, 12, 13, 14, 15) is avoided during pressurization of the first chamber (9).
 12. A gas dryer with a valve as claimed in any one of the preceding claims.
 13. A pressure regulator with a valve as claimed in any one of claims 1 to
 11. 14. A compressed air supply device with a valve as claimed in any one of claims 1 to
 11. 15. A compressed-air operated brake system or pneumatic suspension system of a vehicle with a valve as claimed in any one of claims 1 to
 11. 